1. Field of the Invention
The present invention relates to a liquid crystal display device and a method of assembling the same, and particularly, to an edge type liquid crystal display device, in which a lamp is disposed at a side of the liquid crystal display device, and a method of assembling the same.
2. Background of the Invention
In the recent information age, displays are becoming more and more important as a visual information transmission media. In order to hold an important position in the future, the displays have to meet the following conditions such as a low power consumption, a thin thickness, a light weight, a high picture quality and so on.
The displays are categorized into luminous types, such as a CRT (cathode ray tube), EL (electroluminescent), LED (light emitting diode), VFT (vacuum fluorescent display), FED (field emission display), and PDP (plasma display panel), that emit light by themselves, and non-luminous types, such as a liquid crystal display device, that does not emit light by themselves.
A liquid crystal display (LCD) device displays an image by using optical anisotropy of a liquid crystal material. In addition, the LCD device has better viewing characteristic and has lower average power consumption and heat generation than CRTs having the same screen size. The LCD devices are drawing great attention as one of the next generation display devices along with PDPs.
A liquid crystal material used in the LCD device is not a spontaneous light emitting material, but material receptive of light for displaying an image by modulating an amount of external light. Thus, in the conventional LCD device, an additional light source for irradiating light to a LCD panel, that is, a backlight unit is required.
Hereinafter, the liquid crystal display device will be described in detail.
Unless specially mentioned below, in a completed liquid crystal display device, a portion where a lamp is disposed is called a lower part, and a portion where a liquid crystal display panel is disposed is called an upper part.
The liquid crystal display device largely includes a liquid crystal display panel having liquid crystal injected between an array substrate and a color filter substrate, for outputting an image, a backlight unit installed at a lower portion of the liquid crystal display panel to emit light to the front surface of the liquid crystal display panel, and a plurality of case parts for fixing and coupling the liquid crystal display panel and the backlight unit to each other.
The function of the backlight unit is to produce a flat light having a uniform brightness from a lamp used as a light source, and the thickness and power consumption of the liquid crystal display panel are dependent upon how thin the profile of the backlight unit is and how efficiently light is used.
The backlight units are classified into an edge type and a direct type according to the position of a light source relative to a display plane. In the edge-type device, a light source is disposed at least one side of the liquid crystal display panel, and light is reflected, diffused, and collected through a reflection plate, a light guide plate, and sheets to be transmitted to the front surface of the liquid crystal display panel.
Hereinafter, a structure of the edge type liquid crystal display device will be described in detail with reference to the drawings.
FIG. 1 is a perspective view schematically showing a structure of a general edge type liquid crystal display device. FIG. 2 is a view schematically showing a cross section taken along line A-A′ in the general edge type liquid crystal display device shown in FIG. 1.
For the convenience of explanation, FIGS. 1 and 2 show a state in which the liquid crystal display device is turned over such that the top may face down.
As shown therein, the general edge type liquid crystal display device includes a main support 50 having a stepped coverage face formed therein, a backlight unit and a liquid crystal display panel 10 that are sequentially stacked on the stepped coverage face of the main support 50, a guide panel 30 disposed between the backlight unit and the liquid crystal display panel 10 to support the liquid crystal display panel 10 and secured to a side of the main support 50, and a top case (not shown) for covering and fixing the upper edge of the liquid crystal display panel 10 and the guide panel 30.
The main support 50 is a mold material made from plastic, and its inner lateral wall is molded into a stepped coverage face. The backlight unit and the liquid crystal display panel 10 are sequentially stacked on the stepped coverage face of the main support 50. In addition, a wire fixation part 55 for accommodating and fixing a wire 45 of the lamp assembly 42 is formed at one side of the main support 50.
In addition, the backlight unit includes a lamp (not shown) which is supplied with power from an external power source to irradiate light, a light guide plate 43 which guides light incident through a side face facing the lamp to the liquid crystal display panel 10, a lamp assembly 42 including the lamp and the wire 45 for supplying power to the lamp, a reflecting sheet 41 disposed at the rear surface of the light guide plate 43, a plurality of optical sheets 44 to improve the efficiency of the light coming out of the light guide plate 43, thereby illuminating the liquid crystal display panel 10.
The lamp assembly 42 includes a lamp including an L-shaped or straight glass tube and a high voltage electrode and a low voltage electrode formed at both ends of the glass tube, a high voltage wire 45a connected to the high voltage electrode of the lamp by soldering, and a low voltage wire 45b connected to the low voltage electrode of the lamp by soldering.
The high and low voltage electrodes soldered with the wires 45a and 45b are covered with an insulating holder. Further, the high and low voltage wires 45a and 45b are connected to outside of the LCD device, for example, to a connector through the wire fixation part 55 formed at the main support 50.
The wire fixation part 55 formed at the main support 50 has a reversed L-shaped structure by being extended to the inside of the main support 50. A space between an end of the wire fixation part 55 and the inside of the main support 50 forms an insertion part 51 through which the wire 45 is inserted.
However, the wire 45 inserted through the insertion part 51 and accommodated in the main support 50 cannot prevent movement of the wire 45 in the accommodating direction (z-axis direction) of the wire 45, and hence the accommodated wire 45 comes off upon a pre-delivery inspection or upon handling.
Hereupon, if the width of the insertion part 51 is decreased in order to prevent the wire 45 from coming off, a contraction tube covering the wire 45 is torn apart upon insertion or a stress is concentrated on a weak portion to cause deformation.
As seen above, unless the wire 45 accommodated in the wire fixation part 55 is forcedly fixed by attaching a tape or inserting a fixing foam, there is the possibility that the accommodated wire 45 may come off upon securing for an inspection during a module process or while handling the product.
However, in case of inserting a fixing foam, the tact time increases due to an additional process in the backlight manufacturing process, and the cost for an additional single item and the cost for the additional process are incurred.